Answer:
C) 10,500 years.
Explanation:
- The decay of cobalt-60 is a first order reaction.
- The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5272 year) = 1.314 x 10⁻⁴ year⁻¹.
The integration law of a first order reaction is:
kt = ln [A₀]/[A]
k is the rate constant = 1.314 x 10⁻⁴ year⁻¹.
t is the time = ??? years.
[A₀] is the initial percentage of cobalt-60 = 25.0 g.
[A] is the remaining percentage of cobalt-60 = 6.25 g.
∵ kt = ln [Ao]/[A]
∴ (1.314 x 10⁻⁴ year⁻¹)(t) = ln (25.0 g)/(6.25 g)
(1.314 x 10⁻⁴ year⁻¹)(t) = 1.386.
∴ t = 1.386/(1.314 x 10⁻⁴ year⁻¹) = 10,550 years ≅ 10,500 years.
First c<span>alculate the mole fraction of each substance:
acetone: 2,88 mol </span>÷ (2,88 mol + 1,45 mol) = 0,665.
cyclohexane: 1,45 ÷ (2,88 mol + 1,45 mol) = 0,335.
Raoult's Law:
P(total) = P(acetone) · χ(acetone) + P(cyclohexane) · χ(cyclohexane).
P(total) = 229,5 torr · 0,665 + 97,6 torr · 0,335.
P(total) = 185,3 torr.
χ for acetone: 229,5 torr · 0,665 ÷ 185,3 torr = 0,823.
χ for cyclohexane: 97,6 torr · 0,335 ÷ 185,3 torr = 0,177.
Answer:
eye wash: if you get chemicals in your eyes it helps to clean it
chemical/safety shower; If chemical gets on your skin everywhere you need to take a shower immediately so it helps you get rid of the chemicals on your skin
fire extinguisher: if something cashes on fire you need that to extenguish it
Explanation:
Answer:
Calculate the frequency of light having wavelength of 456 nm.
1.22*10^8nm
Explanation:
Multiply the weight of the object by the distance it traveled to find the amount of work output. For the example: 10 lbs. x 1 foot = 10 foot-pounds. Find the work efficiency by dividing the work output by the work input and multiplying by 100.
